JP2007187003A - Fluid delivery device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To simplify a structure of a fluid delivery device and keep delivery quantity of fluid substantially constant. <P>SOLUTION: The fluid delivery device 10 includes a delivery mechanism 18 provided with a cylinder vessel 16 and a servo motor 40, an inlet side valve 20 and an outlet side valve 22. When the inlet side valve 20 is opened, grease is introduced into the cylinder vessel 16. Boundary face of the grease rises while pushing a piston at a time of introduction. When filling of the grease is completed, the inlet side valve 20 is shut off and the outlet side valve 22 is opened, then the piston is lowered by increase of rotary energizing force of the servo motor 40. And, as a result, the grease is delivered through a delivery tube 14. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a fluid discharge device that discharges and supplies a fluid that flows in a flow passage once.

  In a vehicle body, a constant velocity joint is interposed between rotating shafts in a driving force transmission mechanism that transmits a driving force from an engine such as an internal combustion engine to a tire. One rotating shaft is connected to an outer member constituting the constant velocity joint, and an inner member constituting the constant velocity joint is fitted to the tip of the other rotating shaft. A predetermined part of the inner member is slidably engaged with the inner wall of the opening end of the outer member, so that the rotating shafts are connected to each other so as to be displaceable.

  Here, from the opening end of the outer member to the rotation shaft, the outer member is covered with a rubber or resin joint boot. By this joint boot, the connecting portion between the rotating shafts is protected from rainwater, mud, stones and the like. The joint boot is filled with grease that provides lubricity when the inner member is in sliding contact with the outer member, and also acts to reduce frictional heat associated with the sliding contact.

  The grease is supplied into the joint boot before the joint boot is fastened to the outer member and the rotating shaft via the fastening band. As the grease supply means used at this time, an air-type fixed discharge device that derives grease by compressed air is widely known (for example, see Patent Document 1).

  In this type of air type quantitative discharge device, when the discharge of grease stored in the barrel is repeated and the amount thereof is reduced, the amount of compressed air introduced into the barrel increases. Along with this, the ultimate pressure of the grease is lowered, and as a result, the grease is insufficiently pressurized and the discharge amount is lowered.

  In order to solve such a problem, Patent Document 2 proposes correcting the volume of the air chamber of the barrel. That is, in the technique described in Patent Document 2, the piston is moved in response to the decrease in the discharged liquid and the drop in the liquid level.

Japanese Utility Model Publication No. 6-10699 Japanese Utility Model Publication No. 6-24740

  In the technique described in Patent Document 2, the position of the descending liquid level is detected by a sensor. Therefore, when the detection value of the sensor shows a value different from the actual value due to disturbance or the like, the movement amount of the piston becomes excessive or insufficient. In addition, there is a time lag from when the sensor detects the position of the liquid level until the amount of movement of the piston is determined, so if the liquid level drops further during this time, the amount of movement of the piston is insufficient Resulting in.

  As described above, in the quantitative discharge device according to the prior art, the problem that it is not easy to make the discharge amount of the fluid constant is obvious.

  The present invention has been made to solve the above-described problems, and an object of the present invention is to provide a fluid discharge device capable of discharging a fluid in a substantially constant amount with a simple configuration.

In order to achieve the above-mentioned object, the present invention is a fluid discharge device that is interposed in a flow passage through which a fluid flows, and that discharges and supplies the fluid after temporarily storing the fluid,
A container for storing the fluid,
First opening and closing means for opening and closing the inlet side to the container in the flow path;
Second opening and closing means for opening and closing the outlet side from the container in the flow path;
A piston for discharging the fluid from the container when the second opening / closing means is open;
A servomotor for moving the piston forward in at least the direction of discharging the fluid;
A ball screw that is urged to rotate under the action of the servo motor;
Have
When the servomotor urges the ball screw to rotate, the piston moves forward by being pressed by a nut that is displaced along the ball screw to discharge the fluid.

  In this fluid discharge device, the ball screw is urged to rotate under the action of the servomotor, and the piston is pressed against the nut that is displaced along with this, so that the fluid introduced into the container is discharged. Therefore, by controlling the amount of rotation of the ball screw via the servo motor, it becomes easy to control the amount of displacement of the nut and hence the amount of fluid discharged. Since this type of control is relatively easy for the servo motor, the amount of fluid discharged from the container can be maintained substantially constant by employing the servo motor.

  There is no particular need to set the displacement amount of the nut so that the entire amount of the fluid introduced into the container is discharged. That is, the amount of displacement of the nut, in other words, the amount of rotation of the ball screw may be controlled so that, for example, only 80% of the total amount of fluid introduced is discharged. Since the servo motor that can be controlled with high accuracy is employed as described above, the accuracy of discharging the fluid from the container is maintained even in this case.

  Furthermore, it is preferable that the piston and the ball screw are operable independently of each other, and the piston is pushed backward from the fluid introduced into the container and directed toward the ball screw. In this case, when the fluid is not introduced into the container by a predetermined amount, the displacement amount (retraction operation amount) of the piston becomes small and is separated from the ball screw. By confirming this separation, it is possible to recognize that an abnormality has occurred in the introduction amount of the fluid.

  In this case, there may be further provided distance measuring means for measuring the distance between the nut and the piston, and warning means for issuing a warning when the distance measured by the distance measuring means is equal to or greater than a preset distance. preferable. This is because it is extremely easy to perceive that an abnormality has occurred in the amount of fluid introduced.

  A preferred example of the fluid is grease. In this case, a preferred example of the member that receives the discharged grease is a joint boot that covers one end of the constant velocity joint.

  According to the present invention, the fluid in the container is discharged by applying a predetermined pressing force to the piston under the action of a ball screw whose rotation amount is controlled to a predetermined amount via a servo motor. . For this reason, the forward movement amount of the piston can be easily controlled, and the discharge amount of the fluid can be maintained substantially constant.

  The above effect can be obtained even when the entire amount of the fluid introduced into the container is not discharged.

  Hereinafter, preferred embodiments of the fluid discharge device according to the present invention will be described and described in detail with reference to the accompanying drawings.

  FIG. 1 shows a schematic overall front view of the fluid discharge apparatus according to the present embodiment. The fluid discharge device 10 is disposed, for example, in a grease supply line for supplying grease into a joint boot that covers from the outer member of the constant velocity joint to the rotating shaft. That is, the fluid discharge device 10 is interposed between the piping tubes 12 and 14 through which the grease flows. In the following, for convenience of explanation, the piping tubes 12 and 14 are referred to as an introduction tube 12 and a discharge tube 14, respectively. A predetermined fluid pressure is always applied to the grease flowing through the introduction tube 12.

  The fluid discharge device 10 includes a discharge mechanism 18 including a cylinder container 16, and an inlet side valve 20 and an outlet side valve 22 as opening / closing means. The discharge mechanism 18, the inlet side valve 20 and the outlet side valve 22 are provided. Are positioned and fixed by a stay 28 to a support plate 26 provided on the frame 24. A first relay tube 30 and a second relay tube 32 are bridged between the cylinder container 16 and each of the inlet side valve 20 and the outlet side valve 22.

  Furthermore, one end of a piston 34 is inserted into the cylinder container 16. A flange 35 is provided at the other end of the piston 34. Here, FIG. 1 shows a state where the piston 34 is lowered to a predetermined stroke.

  The discharge mechanism 18 includes a ball screw nut 36, a ball screw 38 passed through the ball screw nut 36, and a servo motor 40 for urging the ball screw 38 to rotate. As will be described later, the ball screw nut 36 is displaced in the vertical direction in FIG. 1 while being guided by the ball screw 38 as the ball screw 38 is rotationally biased and stopped under the action of the servo motor 40.

  In the support board 26, guide rails 42 a and 42 b extending along the vertical direction are laid on the side of the ball screw nut 36. Engaging members 44a and 44b connected to both side portions of the ball screw nut 36 are movably engaged with the guide rails 42a and 42b. By this engagement, the ball screw nut 36 is supported by the guide rails 42a and 42b.

  In addition, a lower part of the ball screw nut 36 from a substantially middle part thereof is provided in a hollow shape by forming a frame part 45. As a result, the weight of the ball screw nut 36 is reduced. Further, since the uneven load due to the ball screw nut 36 is eliminated, the load is concentrated at the approximate center of the lower end surface (four-faced bottom surface 46) of the frame portion 45. Is done.

  The upper end surface of the piston 34 is in contact with the lower end surface of the ball screw nut 36, that is, the four-surface bottom surface 46 of the frame portion 45. That is, in this embodiment, the piston 34 is not connected to the ball screw nut 36.

  Further, an eddy current sensor 47 is provided on the four-sided bottom face 46. As will be described later, the eddy current sensor 47 functions as a distance measuring unit that measures the distance between the four-surface bottom surface 46 and the upper end surface of the flange portion 35 provided on the piston 34.

  In the support board 26, the first magnetic sensor 48 and the second magnetic sensor 50 are positioned and fixed near the lower end of the guide rail 42b and slightly above the middle part, respectively.

  The ball screw 38 is connected to the rotation shaft 52 of the servo motor 40. This connection makes it possible to urge and stop the ball screw 38 under the action of the servo motor 40.

  In the above configuration, the servo motor 40 is supported by the stay 28 so that the rotary shaft 52 faces vertically downward. The servo motor 40 is electrically connected to a control circuit (not shown), and is energized and stopped under the control action of the control circuit. The control circuit is also electrically connected to an eddy current sensor 47, a first magnetic sensor 48, a second magnetic sensor 50, and a warning buzzer (not shown).

  The fluid discharge device 10 according to the present embodiment is basically configured as described above, and the operation and effect thereof will be described next.

  The supply of the grease to the fluid discharge device 10 and the discharge of the grease from the fluid discharge device 10 are performed as follows from the state shown in FIG. That is, first, the inlet side valve 20 is opened to fill the cylinder container 16 with grease. The grease that is circulated through the introduction tube 12 with a predetermined pressure applied and is blocked by the inlet side valve 20 passes through the first relay tube 30 and the cylinder when the inlet side valve 20 is opened. It is introduced into the container 16.

  With this introduction, the interface of grease rises in the cylinder container 16 and starts to press the piston 34. When the introduction of the grease is continued and finally the pressing force of the grease on the piston 34 exceeds the pressing force of the piston 34 on the grease, the piston 34 rises, in other words, starts to move backward.

  The servo motor 40 is biased in advance, so that the ball screw nut 36 is displaced upward in FIG. 1 at a speed corresponding to the rising speed of the piston 34 while being guided by the guide rails 42a and 42b. . For this reason, the state where the upper end surface of the piston 34 is in contact with the four-surface bottom surface 46 of the ball screw nut 36 is maintained. In this case, since the ascending speed of the piston 34 is relatively slow, it is also possible to avoid a so-called squealing sound accompanying the ascent of the piston 34. In addition, it is possible to suppress deterioration with time of the constituent members of the discharge mechanism 18 including the piston 34.

  During this rise, the eddy current sensor 47 constantly measures the distance between the upper end surface of the flange portion 35 of the piston 34 and the four-surface bottom surface 46, and the result is sent as a signal to the control circuit.

  Here, when a predetermined amount of grease is not introduced, the amount of upward displacement (reverse movement amount) of the piston 34 becomes small. For this reason, as shown in FIG. 2, the upper end surface of the piston 34 is separated from the four-surface bottom surface 46 of the ball screw nut 36. Finally, when the distance between the flange 35 measured by the eddy current sensor 47 and the four-sided bottom surface 46 is equal to or greater than the allowable limit value input in advance to the control circuit, the control circuit activates the warning buzzer. A control signal is issued. The operator can recognize that an abnormal amount of grease has been introduced by perceiving the sound of the warning buzzer.

  When the servo motor 40 rotates by a predetermined amount due to the ball screw nut 36 being raised to the predetermined position shown in FIG. 3, the servo motor 40 transmits a transmission signal “the predetermined amount of rotation is completed” to the control circuit. To Upon receiving this, the control circuit determines that “the lifting operation of the piston 34 up to a predetermined stroke has been completed as a predetermined amount of grease is filled”, and issues a control signal for closing the inlet side valve 20. As a result, the inlet side valve 20 is closed, and the supply of grease to the cylinder container 16 is stopped.

  Thus, by detecting that the servo motor 40 has rotated a predetermined amount and stopping the supply of grease, a substantially desired amount of grease can be filled in the cylinder container 16. That is, according to the present embodiment, it becomes extremely easy to control the filling amount of grease to be substantially constant. In addition, when an abnormality in the amount of grease introduced occurs, the operator can recognize the warning buzzer.

  Next, the control circuit issues a signal for opening the outlet side valve 22. Further, the control circuit issues a control signal for increasing the rotation urging force of the servo motor 40, whereby the ball screw 38 is urged to rotate in the forward direction.

  Following this, the ball screw nut 36 descends along the guide rails 42a and 42b. As a result, the piston 34 is displaced downward, that is, moves forward to press the grease in the cylinder container 16. The pressed grease flows through the second relay tube 32 and the outlet side valve 22 to the discharge tube 14. Of course, while the piston 34 is displaced downward, it is detected by the eddy current sensor 47 that the four-surface bottom surface 46 is in contact with the upper end surface of the flange portion 35.

  The piston 34 descends until the rotation shaft 52 of the servo motor 40 rotates by a predetermined amount, in other words, until a predetermined amount of grease filled in the cylinder container 16 is derived, and returns to the state shown in FIG. On the other hand, the opening end (not shown) of the discharge tube 14 is inserted into the joint boot, and therefore the grease led out to the discharge tube 14 is discharged toward the inside of the joint boot.

  On the other hand, the servo motor 40 that has rotated the rotary shaft 52 by a predetermined amount issues a transmission signal to the control circuit that “the lowering operation of the piston 34 to the predetermined stroke has been completed”. Upon receiving this transmission signal, the control circuit reduces the rotational urging force of the servo motor 40 and closes the outlet side valve 22.

  Thus, in the present embodiment, the piston 34 is displaced under the control action of the servo motor 40. Thereby, the discharge amount of grease can be made substantially constant.

  That is, according to the fluid discharge device 10 according to the present embodiment, both the filling amount and the discharge amount of grease can be maintained substantially constant. Therefore, the amount of grease discharged toward the joint boot can be made substantially constant.

  In the above displacement operation, when the ball screw nut 36 is excessively displaced upward and the predetermined part reaches the installation position of the second magnetic sensor 50, the second magnetic sensor 50 that has detected the arrival of the predetermined part has the control function. Send an “abnormal rise” signal to the circuit. On the other hand, when the ball screw nut 36 is displaced excessively downward and a part that is the same as or different from the predetermined part reaches the installation position of the first magnetic sensor 48, the first magnetic sensor 48 sends “ An “abnormal descent” signal is issued. Upon receiving this signal, the control circuit sends a warning signal to the warning buzzer and forcibly stops the servo motor 40.

  In the above-described embodiment, grease has been described as an example of the fluid. However, the fluid is not particularly limited as long as it can flow. That is, it may be a liquid or a gas, or may be a viscoelastic body such as an adhesive or a slurry.

  Further, the member that receives the fluid is not particularly limited to the joint boot. For example, if the adhesive is to be discharged, the adhesive may be discharged toward the workpiece to be joined.

  Further, the upper end of the piston 34 and the lower end of the ball screw nut 36 may be connected. In this case, the servo motor 40 not only moves the piston 34 forward via the ball screw nut 36 but also contributes to the backward movement. In this configuration, when a detecting means for detecting that a predetermined amount of grease (fluid) is introduced into the cylinder container 16, for example, a sensor or the like is provided, the grease (fluid) exceeding the predetermined amount It is preferable because it can be surely avoided that the grease is introduced into the container 16 or the amount of grease (fluid) introduced into the cylinder container 16 is less than a predetermined amount.

It is a general | schematic whole front view of the fluid discharge apparatus which concerns on this Embodiment. FIG. 3 is an enlarged front explanatory view of a main part showing an enlarged vicinity of a tip end portion of a piston and a lower end portion of a ball screw nut constituting the fluid discharge device of FIG. 1. It is a schematic whole front view which shows the state which the piston which comprises the discharge mechanism of the fluid discharge apparatus of FIG. 1 rose to the predetermined stroke.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Fluid discharge apparatus 12, 14 ... Piping tube 16 ... Cylinder container 18 ... Discharge mechanism 20 ... Inlet side valve 22 ... Outlet side valve 34 ... Piston 35 ... Gutter 36 ... Ball screw nut 38 ... Ball screw 40 ... Servo Motor 42a, 42b ... guide rail 47 ... eddy current sensor 48, 50 ... magnetic force sensor

Claims (4)

A fluid discharge device that is interposed in a flow passage through which a fluid flows, and that discharges the fluid after temporarily storing the fluid,
A container for storing the fluid,
First opening and closing means for opening and closing the inlet side to the container in the flow path;
Second opening and closing means for opening and closing the outlet side from the container in the flow path;
A piston for discharging the fluid from the container when the second opening / closing means is open;
A servomotor for moving the piston forward in at least the direction of discharging the fluid;
A ball screw that is urged to rotate under the action of the servo motor;
Have
The piston discharges the fluid by moving forward by being pressed by a nut that is displaced along the ball screw when the servo motor urges the ball screw to rotate. apparatus.   2. The fluid discharge device according to claim 1, wherein the piston is retreated in a direction toward the ball screw by being pressed from the fluid introduced into the container. .   The fluid discharge device according to claim 2, wherein a distance measuring means for measuring a distance between the nut and the piston, and a warning when the distance measured by the distance measuring means exceeds a preset distance. A fluid discharge device further comprising warning means for emitting.   The fluid discharge device according to any one of claims 1 to 3, wherein the grease as the fluid is discharged toward an inside of a joint boot that covers one end of a constant velocity joint. Fluid discharge device.

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